org.springframework.web.context.support.ServletContextResource Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.context.support;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import javax.servlet.ServletContext;
import org.springframework.core.io.AbstractFileResolvingResource;
import org.springframework.core.io.ContextResource;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.util.WebUtils;
/**
* {@link org.springframework.core.io.Resource} implementation for
* {@link javax.servlet.ServletContext} resources, interpreting
* relative paths within the web application root directory.
*
* Always supports stream access and URL access, but only allows
* {@code java.io.File} access when the web application archive
* is expanded.
*
* @author Juergen Hoeller
* @since 28.12.2003
* @see javax.servlet.ServletContext#getResourceAsStream
* @see javax.servlet.ServletContext#getResource
* @see javax.servlet.ServletContext#getRealPath
*/
public class ServletContextResource extends AbstractFileResolvingResource implements ContextResource {
private final ServletContext servletContext;
private final String path;
/**
* Create a new ServletContextResource.
*
The Servlet spec requires that resource paths start with a slash,
* even if many containers accept paths without leading slash too.
* Consequently, the given path will be prepended with a slash if it
* doesn't already start with one.
* @param servletContext the ServletContext to load from
* @param path the path of the resource
*/
public ServletContextResource(ServletContext servletContext, String path) {
// check ServletContext
Assert.notNull(servletContext, "Cannot resolve ServletContextResource without ServletContext");
this.servletContext = servletContext;
// check path
Assert.notNull(path, "Path is required");
String pathToUse = StringUtils.cleanPath(path);
if (!pathToUse.startsWith("/")) {
pathToUse = "/" + pathToUse;
}
this.path = pathToUse;
}
/**
* Return the ServletContext for this resource.
*/
public final ServletContext getServletContext() {
return this.servletContext;
}
/**
* Return the path for this resource.
*/
public final String getPath() {
return this.path;
}
/**
* This implementation checks {@code ServletContext.getResource}.
* @see javax.servlet.ServletContext#getResource(String)
*/
@Override
public boolean exists() {
try {
URL url = this.servletContext.getResource(this.path);
return (url != null);
}
catch (MalformedURLException ex) {
return false;
}
}
/**
* This implementation delegates to {@code ServletContext.getResourceAsStream},
* which returns {@code null} in case of a non-readable resource (e.g. a directory).
* @see javax.servlet.ServletContext#getResourceAsStream(String)
*/
@Override
public boolean isReadable() {
InputStream is = this.servletContext.getResourceAsStream(this.path);
if (is != null) {
try {
is.close();
}
catch (IOException ex) {
// ignore
}
return true;
}
else {
return false;
}
}
@Override
public boolean isFile() {
try {
URL url = this.servletContext.getResource(this.path);
if (url != null && ResourceUtils.isFileURL(url)) {
return true;
}
else {
return (this.servletContext.getRealPath(this.path) != null);
}
}
catch (MalformedURLException ex) {
return false;
}
}
/**
* This implementation delegates to {@code ServletContext.getResourceAsStream},
* but throws a FileNotFoundException if no resource found.
* @see javax.servlet.ServletContext#getResourceAsStream(String)
*/
@Override
public InputStream getInputStream() throws IOException {
InputStream is = this.servletContext.getResourceAsStream(this.path);
if (is == null) {
throw new FileNotFoundException("Could not open " + getDescription());
}
return is;
}
/**
* This implementation delegates to {@code ServletContext.getResource},
* but throws a FileNotFoundException if no resource found.
* @see javax.servlet.ServletContext#getResource(String)
*/
@Override
public URL getURL() throws IOException {
URL url = this.servletContext.getResource(this.path);
if (url == null) {
throw new FileNotFoundException(
getDescription() + " cannot be resolved to URL because it does not exist");
}
return url;
}
/**
* This implementation resolves "file:" URLs or alternatively delegates to
* {@code ServletContext.getRealPath}, throwing a FileNotFoundException
* if not found or not resolvable.
* @see javax.servlet.ServletContext#getResource(String)
* @see javax.servlet.ServletContext#getRealPath(String)
*/
@Override
public File getFile() throws IOException {
URL url = this.servletContext.getResource(this.path);
if (url != null && ResourceUtils.isFileURL(url)) {
// Proceed with file system resolution...
return super.getFile();
}
else {
String realPath = WebUtils.getRealPath(this.servletContext, this.path);
return new File(realPath);
}
}
/**
* This implementation creates a ServletContextResource, applying the given path
* relative to the path of the underlying file of this resource descriptor.
* @see org.springframework.util.StringUtils#applyRelativePath(String, String)
*/
@Override
public Resource createRelative(String relativePath) {
String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
return new ServletContextResource(this.servletContext, pathToUse);
}
/**
* This implementation returns the name of the file that this ServletContext
* resource refers to.
* @see org.springframework.util.StringUtils#getFilename(String)
*/
@Override
@Nullable
public String getFilename() {
return StringUtils.getFilename(this.path);
}
/**
* This implementation returns a description that includes the ServletContext
* resource location.
*/
@Override
public String getDescription() {
return "ServletContext resource [" + this.path + "]";
}
@Override
public String getPathWithinContext() {
return this.path;
}
/**
* This implementation compares the underlying ServletContext resource locations.
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof ServletContextResource)) {
return false;
}
ServletContextResource otherRes = (ServletContextResource) other;
return (this.servletContext.equals(otherRes.servletContext) && this.path.equals(otherRes.path));
}
/**
* This implementation returns the hash code of the underlying
* ServletContext resource location.
*/
@Override
public int hashCode() {
return this.path.hashCode();
}
}